Решение методом подстановки.<span>{<span><span>x−y=3</span><span>x+y=5</span></span></span><span>{<span><span>x=y+3</span><span>x+y=5</span></span></span><span>{<span><span>x=y+3</span><span><span>(<span>x+3</span>)</span>+y=5</span></span></span><span>{<span><span>x=y+3</span><span>2y−2=0</span></span></span><span>{<span><span>x=y+3</span><span>y=1</span></span></span><span>{<span><span>x=4</span><span>y=1</span></span></span>Ответ:<span>(<span>4;1</span>)
</span><span>{<span><span>x−y=3</span><span>x+y=5</span></span></span>Вычитаем уравнения:<span><span>−<span>{<span><span>x−y=3</span><span>x+y=5</span></span></span></span><span>(x−y)−(x+y)=3−5</span></span><span>−2y=−2</span><span>y=1</span>Подставиим найденную переменную в первое уравнение:<span>x−(1)=3</span><span>x=4</span>Ответ:<span><span>(<span>4;1</span>)</span></span>